An object of the present invention is to provide a method and an apparatus for marking an electric wire at a low cost. An apparatus 1 for marking an electric wire forms a band mark 21 on a part of an outer face 5a of the electric wire 3. The band mark 21 is formed along the entire circumference of the part of the outer face 5a of the electric wire 3. The marking apparatus 1 tightens the electric wire 3 in a state where a tensile force is applied in a longitudinal direction. The marking apparatus 1 includes a nozzle 35 for injecting coloring agent toward an uppermost position 10 of the outer face 5a of the electric wire 3. The nozzle 35 has an open end 42 which is opposed to the electric wire 3 and capable of passing the coloring agent. A straight line L extending between a center C1 of the open end 42 and a center C2 of the electric wire 3 lies along a vertical direction. <IMAGE>